The present invention is directed to an improved wick holder used in a lubricating system for lubricating the axle-journal surface mounted in a support bearing of a locomotive traction motor. The wick holder supports and mounts a central lubricating wick having a lower end portion or section received in an oil reservoir, which oil, via capillary action, is delivered by the wick to the axle-journal surface by means of a window formed in the shell of the traction motor support bearing. The other, upper wick-face section of the wick is received in the window for contact against the axle-journal surface, to thereby provide the proper lubrication.
Examples of this lubricating system are disclosed in the U.S. Pat. Nos. 2,980,472; 3,827,769; 3,905,659; 4,229,056; and 5,082,089. One such prior-art system is also shown in FIG. 1, and is indicated generally by reference numeral 10, and includes an oil reservoir 12 for storing lubricant, and a carrier assembly 14 connected to the axle cap 16 of a friction support bearing 18 used for mounting a locomotive traction motor to the wheel axle assembly. The carrier assembly 14 has a spring 22, such as a coil or torsion spring, that biases a wick-holder unit 34 toward a window 26 formed in the shell of the friction support bearing 18, through which window oil is delivered to the axle-journal surface 37 mounted in the friction support bearing.
The wick-holder unit consists of a slide bracket element or member 32 which is mounted for sliding movement in the carrier assembly 14, a wick holder member 34 of arcuate shape that is connected to the slide bracket element 32, and a felt wick 36 having an upper section of similar arcuate shape mounted in the wick holder 34.
The above-described wick lubricator assembly of the prior art, however, has serious shortcomings. Specifically, these prior art oil-lubricating delivery systems have decreasing ability to deliver a continuous amount of oil to the axle-journal surface area as the oil level in the journal box is consumed over time, as the oil level in the oil reservoir decreases, even though the wick had initially absorbed oil to saturation.
When a new traction motor/axle wheel set of a locomotive is placed into service, it has approximately twelve pints of journal oil added to the bearing oil reservoir. Capillary-oil lift is typically less than two inches. During normal operation, the oil is consumed and the oil level in the reservoir continues to drop, resulting in reduced oil-saturation of the felt wick. As a result, the oil delivery-rate is reduced in inverse proportion to the increased required oil-wicking height. The result of this reduced oil delivery can be a repetitive cycle of reduction in the load bearing capacity of the journal and an increase in the operating temperature of the bearing each time the locomotive accumulates mileage between normal servicing. As a result of this reduction of lubrication delivered to the journal, the margin of excess bearing capacity can be reduced such that a condition is created that can end in a failure of the bearing and axle.
It would, therefore, be advantageous to provide an improved wick-lubricating delivery system for an axle-journal surface supported by a friction bearing of a locomotive traction motor that diminishes the adverse effect of oil depletion in the journal box and oil reservoir, in order to continue to supply the requisite lubricating oil to the axle-journal, thereby reducing railroad operating expenses by improving reliability and length of service of the existing traction motor/axle-wheel set combination.